Inspection of raceway surfaces and the like



Nov. 7, 1950 T. R. WELCH 2,529,360

INSPECTION 0F RACEWAY SURFACES A'ND THE LIKE Filed Jan. 9, 1946 /NVENTOQ THEOoO/QE e. WELCH, BY c//a/ze/ H/ ATTORNEY Patented Nov. 7, 1950 INSPECTION F RACEWAY SURFACES LIKE ANDTHE Theodore R. Welch, Denville, N. J., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application January 9, 1946, Serial No. 639,959

6 Claims. l

This invention relates to inspection of raceway surfaces and thelike and comprises all of the features of novelty herein disclosed and claimed. An object of the invention is to provide an improved apparatus and method for detecting chatter marks and other surface defects on the inner surface of an opaque ring. To these ends and also to improve generally upon inspecting apparatus and methods, the invention consists in the various matters hereinafter described and claimed. In its broader aspects thelnyention is not necessarily limited to the specic construction selected for illustrative purposes in the accompanying drawings in which Fig. l is a cross sectional view of the apparatus and Fig. 2 is a front elevation of a portion of the apparatus to smaller scale.

Referring to the drawings, the letter W indicates the work and the numeral 2 indicates a pair of parallel angle iron supports or guide rails supported near their ends by the oppositeside walls 4 of a hood which is preferably made of wood and has a rear wall 6 and a cover (not shown). Within this hood is a light-confining housing with a short front wall, a tall rear wall and an inclined top wall having a frosted glass screen 8 or the like inserted therein. This screen is in a plane parallel to the central plane of the work and to the supporting flanges of the guide rails 2 which project through openings in the side walls 4 as indicated in Fig. 2 so that the work pieces can be introduced successively at one side of the housing and pushed out at the other side. Projecting from the inner housing is a bracket 9 supporting a lamp socket I0 for a lamp which has a nearly point source of light at I2 close to the plane of the adjacent side of the ring. Cemented or otherwise secured to the bottom legs of the angle irons 2 is a clear glass Il on which is centrally supported a circular shield I6 of opaque material. Between the shield and the adjacent edge of the work is an annular space just large enough for direct rays of light to reach the interior surface of the work. In other words, the shield is of smaller diameter than the interior surface of the ring to block the direct passage of light through the ring while allowing light to impinge on the interior surface for reflection ,therefrom. The shield is flat and wholly outside lof the outline of the work so that it oiers no ob- 'struction to the sliding of the work radially to ,inspecting position.

The work pieces W are herein shown as outer race rings for self-aligning roller bearings but this is merely illustrative. These rings have an interior surface which is a non-equatorial segment of a sphere so that the raceway surface tapers cr enlarges from the lower end of the ring to the upper end. The light from the point source I2 is reflected from the raceway surface onto the screen 8 whose plane is some distance from the work, direct rays of light being excluded from passage through the ring and from the inspectors eyes by the shield I6. The point source of light lies in the extended axis of the work W. The course of the rays of light is indicated by the broken lines and it will be seen that the reflected rays are spread out between points I8 and 20 and, on perfect work, these points would lie on concentric circles. The common center of thesevcircles is in line with the axis of the work and a magnified image of imperfections appears on the screen.

The work is placed on the guide rails at one end and. pushed along by following pieces. The work in the middle location over the light can be easily centered when necessary by manipulating the end pieces. Surface defects vin the work are readily detected by irregularities in the light patterns. Chatter marks on the work are in the form of shallow depressions or indentations around the periphery and are usually spaced uniformly. Chatter marks are shown on the screen principally by a scalloped pattern of the reflected light. Some chatter marks are shown by alternate shady and bright spots probably caused by the small depressions acting as individual reflectors which form concentrated beams. The defects in the surface are magnied on the screen and some are so readily and quickly discernible that the work pieces can be inspected while in motion along the guide rails. Rings for other types of antifricton bearings and other articles can be inspected by the method indicated. When the guide rails are too widely spaced to center the Work, a shim or ller plate may be inserted next to the vertical flange of the lower angle iron.

I claim:

1. In apparatus for inspecting the interior surface of rings, a pair of guide rails to support the rings for sliding movement, a source of light equidistant from the rails in a position to send direct rays against the interior surface of each ring as the latter is slid along the rails, a housing enclosing the light and having a semi-transparent screen on the opposite side of the ring from the source of light to receive light reflected from the interior surface and form an image of such sur- 3 face, and the housing having an opening for thc guide rails and for the insertion of the rings in succession.

2. 'I'he method oi' inspecting the interior surface of a ring for imperfections which consists in directing light from a point source in the ams of the ring to the interior surface, blocking off direct passage of light through the ring, reflecting an annular series of light rays from the interior surface to that side of the ring opposite from the source of light, causing the reiiected rays to-produce a magnified image of the interior surface on a focal plane perpendicular to the ring axis, and observing said'image to detect imperfections in the ring'surface.

` 3. In apparatus for inspecting the interior surface of a ring, a support for the ring, a point Y source of light adjacent to .one side of the support, a circular shield of opaque material inter- .'pos'ed between the source and the ring to obstruct the directpassage of light through the ring, the

'shield being of smaller diameter than the interior surface of the ring to allow light to pass from the source to the interior surface for reflection therefrom, and alfrosted glass screen on that side of the support opposite from the source of light to receive the reflected rays and form an image of the interior surface for inspection.

' 4. In apparatus for inspecting the interior surface of rings, a housing, a ring support in the housing, the housing having a side wall with an lopening to provide for inserting the rings successively into the housing onto the ring support, a point source of light below the support for sending rays against the interior surface of the supported ring, a shield barring the direct passage of light from the source through the central region Yof the ring, and a frosted glass screen permanently xed to the housing on the 'opposite side of the support to receive rays reected from the interior surface and form an image of such surface for inspection.

5. In apparatus for inspecting the interior surface of rings, a housing, spaced ring supporting members in the housing, a point source of light at one side of the space between said members,

the housing having a side wall with an opening aligned with the supporting members to provide for inserting a ring onto said members in a direction radially of the ring, a. at circular shield of smaller diameter than the space between the supporting members for barring direct passage oi light through the ring from the source, the shield being located on that side of the supporting members adjacent to the light source and out of the path of radial insertion of the ring, and a frosted glass screen on the opposite side of the supporting members to receive rays reflected from .the interior surface of the ring and form an image of such surface for inspection.

6. In apparatus for inspecting the interior surface of rings, a housing having side walls provided with openings, guide rails extending through the openings and spaced apart to slidably support a series of rings inserted successively through one of the openings, a point source of light fixed in the housing below the guide rails to direct rays against the interior surface of a ring supported on the rails, an opaque shield between the guide rails to bar the passager of light through the ring without reection from its interior surface, and means on the opposite side of the guide rails from the source of light and farther away from the rails than the light to receive the reflected rays and form a magnied image of the interior surface of the ring.

THEODORE R. WELCH. l

le of this patent:

. UNITED STATES PATENTS Number Name Date 1,332,570 Ray 1 Mar. 2'. 1920 2,321,331 Sweezey 'June 8, 1943 2,332,668 Richards Oct. 26, 1943 FOREIGN PATENTS Number Country Date 701,172 Germany Jan. 10, 1941 new mi 

